Hydropower offers solution to balance wind-powered grid

Norwegian researchers are looking into options to use hydropower plants as batteries to balance European electricity network after further wind power plants are connected to the grid.

According to European data, a total offshore wind power capacity of 3.8 GW was established in Europe by the end of 2011 and the European Wind Energy Association (EWEA) anticipates this amount will rise to 150 GW in the period 2030 to 2050. This is equivalent to the energy produced by about 150 medium-sized coal-fired power stations.

However, as the predictability of wind-power generation depends on the reliability of weather forecast, researchers across Europe have been thinking how balance the power grid for instances where too much or too little energy is generated.

"Today, forecasts of wind velocities provide the only information which gives us any indication of power generation levels from wind farms for the next 24 hours", said Daniel Huertas-Hernando, a scientist at the Scandinavian research institute SITNEF.

"If these prognoses turn out to be wrong, or if bad weather makes generation from the turbines impossible, we will need an effective stand-by source which can fill the energy supply gap at short notice", he said.

The team has analysed how old Norwegian hydropower plants could be used to serve as batteries to cover the fluctuations.

"We don't have to build any more new hydropower plants which have a negative impact on the natural environment", said Huertas-Hernando. “We have calculations that show that we will obtain sufficient capacity if we upgrade our existing hydropower turbines and install pump storage technology.”

A pump storage plant is a hydropower plant which can be repeatedly 'charged' because water can be pumped back into the reservoir after it has flowed through a turbine and released through the turbine again when electricity is needed.

Currently, a northern European offshore power grid is being developed following massive investment into wind power in the Baltic region and around the North Sea. The technology should reduce CO2 emissions by up to 95 per cent by 2050.

In ideal scenario, Norwegian hydropower plants could be connected to this newly established grid.

The SITNEF institute is working on the project, called TWENTIES and funded by the European Union, together with a number industry partners.